According to news reports, Faisal Shahzad, the Pakistani-American charged with trying to use a weapon of mass destruction in the failed Times Square bombing, has told investigators he carried out the attempted bombing to avenge US drone attacks in the North Waziristan tribal region of Pakistan.

Shahzad’s assertion adds more fuel to the simmering controversy over the ethics and effects of increasing reliance by both the CIA and the US military on unmanned drones to launch missile strikes against suspected al-Qaeda and Taliban militants in Afghanistan and Pakistan.

As David Sanger, chief Washington correspondent for the New York Times, asked (“US pressure helps militants overseas focus efforts,” May 7) : “Have the stepped-up attacks in Pakistan—notably the Predator drone strikes—actually made Americans less safe? Have they had the perverse consequence of driving lesser insurgencies to think of targeting Times Square and American airliners, not just Kabul and Islamabad? In short, are they inspiring more attacks on America than they prevent? It is a hard question.”

The Times Square drone connection also follows on last year’s deadly attack on the CIA, when a suicide bomber, a Jordanian doctor linked to al-Qaeda, detonated his explosives at an American base in Khost in eastern Afghanistan, killing himself and seven CIA officers and contractors who were operating at the heart of the covert program overseeing US drone strikes in Pakistan’s northwestern tribal regions.

CIA director Leon Panetta has called lethal drone technology “the only game in town” for going after al-Qaeda, and Obama administration officials have strenuously defended both the legality of the strikes in Pakistan as well as their effectiveness in killing suspected militants. They also deny the drones are responsible for an unacceptable level of civilian deaths.

“In this ongoing armed conflict, the United States has the authority under international law, and the responsibility to its citizens, to use force, including lethal force, to defend itself, including by targeting persons such as high-level al-Qaeda leaders who are planning an attack,’’ Harold Koh, the State Department’s legal adviser, told an audience of international legal scholars on March 25, according to the Wall Street Journal (“US defends legality of killing with drones”).

Since President Obama took office, the CIA has used drones to kill some 400 to 500 suspected militants, according to intelligence officials, the Journal reported. The officials say only some 20 civilians have been killed—a figure critics sharply challenge. In 2009, Pakistani officials said the strikes had killed some 700 civilians and only 14 terrorist leaders, or 50 civilians for every militant. A New America Foundation analysis of reported US drone strikes in northwest Pakistan from 2004 to 2010 says the strikes killed between 830 and 1210 individuals, of whom 550 to 850 were militants, or about two-thirds of the total on average.

More recently, an April 26 story in the Washington Post reported that the CIA has refined its techniques and made technological improvements that are reducing civilian deaths, and this week, in his joint news conference with President Karzai of Afghanistan, President Obama said, “I am ultimately accountable…for somebody who is not on the battlefield who got killed…and so we do not take that lightly. We have an interest in reducing civilian casualties not because it’s a problem for President Karzai; we have an interest in reducing civilian casualties because I don’t want civilians killed.”

Earlier this month, in a May 6 interview on National Public Radio, David Rohde, the New York Times reporter who was held captive for months by the Taliban in northern Pakistan, spoke about the US drone strikes and said, “I saw firsthand in north and south Waziristan that the drone strikes do have a major impact. They generally are accurate. The strikes that went on killed foreign militants or Afghan or Pakistani Taliban that went on around us. There were some civilians killed but generally the Taliban would greatly exaggerate the number of civilians killed. They inhibited their operations. Taliban leaders were very nervous about being tracked by drones. So they are effective in the short-term I would say…I don’t think the answer is, you know, endless drone strikes. The answer is definitely not sending American troops into Pakistan, into the tribal areas. That would just create a tremendous nationalist backlash. It has to be the Pakistanis doing it.”

Ethicists and religious leaders are beginning to challenge the morality of the drone program, arguing it violates international law as well as key precepts of just war theory. The Christian Century, for example, editorialized in mid-May (“Remote-control warfare,” May 18) that while the drone attacks have no doubt killed terrorists and leaders of al-Qaeda, “they raise troubling questions to those committed to the just war principle that civilians should never be targeted.”

Taking aim at one of the aspects of drone warfare that make it so popular with the military and with politicians—that it is a risk-free option for the US military because it avoids American casualties—the Century editors said: “According to the just war principles, it is better to risk the lives of one’s own combatants than the lives of enemy noncombatants.”

The “risk-free” idea is also being challenged. In a recent piece in the Jesuit magazine America (“A troubling disconnection,” March 15), Maryann Cusimano Love, an international relations professor at Catholic University, wrote that military (as opposed to CIA) drone operators suffer post-traumatic stress disorder at higher rates than soldiers in combat zones. “Operators see in detail the destruction and grisly human toll from their work,” she observed, and she quoted an air force commander who said, “There’s no detachment. Those employing the system are very involved at a personal level in combat. You hear the AK-47 going off, the intensity of the voice on the radio calling for help. You’re looking at him, 18 inches away from him, trying everything in your capability to get that person out of trouble.”

The Christian Century editors also noted that drone attacks on civilians have given militants a recruitment tool, citing an opinion piece by counterinsurgency expert David Kilcullen and former army officer Andrew McDonald Exum published last year in the New York Times (May 17, 2009). “Every one of these dead noncombatants represents an alienated family, a new desire for revenge, and more recruits for a militant movement that has grown exponentially even as the drone strikes have increased,” they wrote.

An even more emphatic critic of the use of drones is Mary Ellen O’Connell, an international law professor at the University of Notre Dame. “Neither the Bush administration nor the Obama administration has been persuasive about its legal right to launch attacks in Pakistan,” she wrote in “Flying Blind,” an article also published in America magazine. “Even with the legal right to use military force, drone attacks must also conform to the traditional principles governing the rules of warfare, including those of distinction, necessity, proportion and humanity.’’

O’Connell argues that under the United Nations Charter, resort to military force on the territory of another state, in this case Pakistan, is permitted only when the attacking state is acting in self-defense, acting with U.N. Security Council authorization, or is invited to aid another state in the lawful use of force. “Pakistan did not attack the United States and is not responsible for those who did,” O’Connell wrote. “The United States has no basis, therefore, for attacking in self-defense on Pakistani territory.’’

In addition, she contends that while al-Qaeda is a violent terrorist group, “it should be treated as a criminal organization to which law enforcement rules apply. To do otherwise is violate fundamental human rights principles. Outside of war, the full body of human rights applies, including the prohibition on killing without warning.”

The only basis for the United States to lawfully use force in Pakistan would be if it had the consent of the country’s political leaders. It is not clear whether the US has such a valid invitation, according to O’Connell.

“Pakistan’s president has told US leaders not to attack certain groups that have cooperated with Islamabad,” O’Connell wrote. “The United States has done so anyway, insisting that Pakistan use more military force and threatening to carry out attacks itself if the government refuses. None of this can be squared with international law.”

As recently as May 12, the head of an influential religious party which is a junior partner in Pakistan’s ruling coalition denounced the most recent drone attacks as a violation of Pakistani sovereignty. “The recurring attacks on targets in tribal areas are blatant aggression against Pakistan and the military should shoot down intruding drones,” Maulana Fazlur Rehman, leader of the Jamiat Ulema Islam party told reporters, as reported in the Gulf News.

The case of western Pakistan presents particular challenges, according to O’Connell: “There suspected militant leaders wear civilian clothes, and even the sophisticated cameras of a drone cannot reveal with certainty that a suspect is a militant. In such a situation international humanitarian law gives a presumption to civilian status.”

In an interview, O’Connell suggests that there is confusion about international law versus domestic national security law and that the scarcity of developed ethical analysis and discussion of drone warfare might have to do with the fact that the drone itself is “just a delivery vehicle.” The real ethical issue, she said, is “the greater propensity to kill” made possible by the “video game-like” quality of drone combat.

Gary Simpson, a theology professor at Luther Seminary in St. Paul, Minnesota and the author of “War, Peace, and God: Rethinking the Just War Tradition” (Augsburg Fortress Press, 2007), acknowledges that although he hasn’t yet thought about ethics and drone warfare, “the ongoing evolution of weaponry always poses new questions. It changes the questions about proportionality”—referring to the just war principle that the benefits of war must be proportionate to the expected harm— “and the protection of one’s own forces over against the vulnerability of civilian populations.”

The House Subcommittee on National Security and Foreign Affairs held hearings in March and April on the rise of the drones, the legality of unmanned targeting systems, and the future of war, and US Naval Academy ethics professor Edward Barrett testified that while unmanned weapons systems “are consistent with a society’s duty to avoid unnecessary risks to its combatants,” and they can “enhance restraint” on the part of the soldiers engaged in virtual warfare, they also “could encourage unjust wars” and “could facilitate the circumvention of legitimate authority and pursuit of unjust causes.”

It will be interesting to see whether Congress and the White House continue to involve ethicists and religious thinkers in future deliberations on these issues. Last December, just before President Obama gave his Nobel Peace Prize acceptance speech on themes of just war, the White House gathered religious leaders at the Eisenhower Executive Office Building for what was described as a briefing and discussion of the morality of war, according to the Washington Post. White House staff members took notes for the president.

For now, the Obama administration insists the use of drones in Pakistan is imperative in the fight against terrorism, and Amitai Etzioni, an international relations professor at George Washington University, writing recently in the Joint Force Quarterly (“Unmanned Aircraft Systems: The Moral and Legal Case”), has enumerated many of the reasons and offered multiple lines of supporting argument: “The United States and its allies can make a strong case that the main source of the problem is those who abuse their civilian status to attack truly innocent civilians and to prevent our military and other security forces from discharging their duties,” he says, and “we must make it much clearer that those who abuse their civilian status are a main reason for the use of UAS [unmanned aircraft systems] and targeted killing against them.”

But others, such as Kilcullen and Exum, argue drone combat exacerbates the problem of terrorism and contributes to the instability of Pakistan. “Having Osama bin Laden in one’s sights is one thing,” write Kilcullen and Exum. “Devoting precious resources to his capture or death, rather than focusing on protecting the Afghan and Pakistani populations, is another. The goal should be to isolate extremists from the communities in which they live.”

Missile strikes launched from the comfort of Langley, Virginia, a half a world away from Waziristan, are unlikely to do that and thus, to critics, remain morally problematic.